WKWebView, scrolling the web page to top - ios

Question

I tried this, which should work but doesn't:
webView.scrollView.setContentOffset(CGPoint(x: 0, y: 0), animated: false)
I am working on a browser and have a couple of webViews in kept in stack. Some sites work as expected, start at the top, some do not.
Starts at top: http://leagueoflegends.com/
This one starts a little down, have to manually scroll up: http://euw.leagueoflegends.com/
Extra note, this problem never happens to the first webView. Even if I load the 2nd link and show it as first webView, it doesn't scroll to the middle.

Answer 1

I had a very similar problem when rotating my WKWebView.
After rotation to landscape the view is automatically scrolled to the middle.
I use following workaround to scroll to the top of the page again after rotation:
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
coordinator.animate(alongsideTransition: nil, completion: { (context) in
self.webKitView.evaluateJavaScript("window.scrollTo(0,0)", completionHandler: nil)
})
}
In your case it should work to call this directly after you load your URL.
webKitView.evaluateJavaScript("window.scrollTo(0,0)", completionHandler: nil)
Or if your problem occurs when navigating within the WKWebView, you could use a WKNavigationDelegate (I have not tested this) :
override func viewDidLoad() {
super.viewDidLoad()
// load content of webKitView here and set as view or add as subview
webKitView.navigationDelegate = self
}
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
webKitView.evaluateJavaScript("window.scrollTo(0,0)", completionHandler: nil)
}

Answer 2

Our app uses multiple WKWebView instances and we have also experienced this problem of some pages randomly scrolling to some location down the page.
We were able to work around the problem by having the next webView which will be loading the next page attached to the window hierarchy before loading the URL.
WKWebView* nextWebView = [WKWebView new];
[[[UIApplication sharedApplication] keyWindow] addSubview:webView.view];
[[[UIApplication sharedApplication] keyWindow] sendSubviewToBack:webView.view];
Then when you load your URL:
[nextWebView.view removeFromSuperview];
[controller.view addSubview: nextWebView.view];

Answer 3

I encountered this too. Finally, I fixed this way:
if #available(iOS 11, *) {
webView.scrollView.contentInsetAdjustmentBehavior = .never
}
If you have this issue on iOS 11, try this.

Answer 4

Before iOS 11.0, UIWebView was avilable with delegates to indicate that loading of webView is finished and we can do any operation after loading has been finished.
Now we have WKWebView which doesn't provide any delegate method to notify once your webView has finished loading. Due to this if we do following piece of code then it will not work:
let myURL = URL(string: "https://www.google.com")
let myRequest = URLRequest(url: myURL!)
webView.load(myRequest)
webView.scrollView.setContentOffset(CGPoint(x: 0, y: 0), animated: false)
In this case, webView.load() is a asynchronous function which gets called and code moves further without waiting for its completion. Due to this your call for setContentOffset work but after that when webView finish loading it reset the ContentOffset to default, which is actually (0,0) but I am not sure why your WebView doesn't load from top. But doing code in following manner will may help you:
Extend to WKNavigationDelegate and implement didFinish navigation method in your ViewController and call setContentOffset in that method.
class ViewController: UIViewController, WKNavigationDelegate {
override func viewDidLoad() {
let myURL = URL(string: "https://www.google.com")
let myRequest = URLRequest(url: myURL!)
webView.load(myRequest)
webView.navigationDelegate = self
}
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
webView.scrollView.setContentOffset(CGPoint(x: 0, y: 0), animated: false)
}
}

Answer 5

I would try to use javascript doc for scrolling to top:
NSString *script = #"window.scrollTo(0, 0)";
// UIWebView
// [webView stringByEvaluatingJavaScriptFromString:script];
// WKWebView
[webView evaluateJavaScript:script completionHandler:NULL];

Answer 6

Swift 4
This function is part of the WKWebView's UIScrollView and scrolls to a given rectangle.
scrollRectToVisible(_ rect: CGRect, animated: Bool)
A code example would look like:
let rect: CGRect = CGRect(x: 0, y: 0, width: 1, height: 1)
webView.scrollView.scrollRectToVisible(rect, animated: true)

Answer 7

This seems to happen if the WKWebView is not fully initialized or sized when asked to display a web page.
In my case, I created the web view during loadView in a UIViewController. If I then requested to navigate to a web page during viewDidLoad, the web view appeared scrolled partway down the page. I was able to fix the problem by moving the html request into viewWillAppear: (which is later in the view controller lifecycle).